SAN FRANCISCO – Barry Bonds has little chance of having his perjury case dropped, even though his attorneys are preparing to ask a judge to do that today, legal experts said.

Bonds’ lawyers were scheduled to ask U.S. District Court Judge Susan Illston to dismiss a federal indictment charging him with perjury and obstruction of justice for his grand jury testimony, in which he denied knowingly using illegal performance-enhancing drugs.

Bonds argues that prosecutors unfairly asked confusing, vague and ambiguous questions during his grand jury appearance in December 2003. The former San Francisco Giants star has pleaded not guilty. In court papers, he neither admits nor denies taking the drugs.

If the judge declines to dismiss the charges, Bonds wants prosecutors to streamline the indictment, which cites 19 different instances of Bonds’ alleged lying but only charges him with four counts of perjury and one count of obstruction.

In his papers, Bonds makes detailed attacks on every allegation and complains that each charge should cite only one instance of lying.

“It’s a really smart tactic to pick out every single question and answer,” said University of California, San Francisco law school professor Rory Little, a former federal prosecutor. “Bonds has made a very strong case that there is some duplication and some questions aren’t as well-phrased as they could be.”

But Little and other legal experts said they would be shocked if Bonds succeeds in getting the case dismissed.